Emergence of antibiotic-resistant bacteria is a serious threat to the public health. This is also true for Staphylococcus aureus and other staphylococci. Staphylococcus phages Stab20, Stab21, Stab22, and Stab23, were isolated in Albania. Based on genomic and phylogenetic analysis, they were classified to genus Kayvirus of the subfamily Twortvirinae. In this work, we describe the in-depth characterization of the phages that electron microscopy confirmed to be myoviruses. These phages showed tolerance to pH range of 5.4 to 9.4, to maximum UV radiation energy of 25 µJ/cm2, to temperatures up to 45 °C, and to ethanol concentrations up to 25%, and complete resistance to chloroform. The adsorption rate constants of the phages ranged between 1.0 × 10-9 mL/min and 4.7 × 10-9 mL/min, and the burst size was from 42 to 130 plaque-forming units. The phages Stab20, 21, 22, and 23, originally isolated using Staphylococcus xylosus as a host, demonstrated varied host ranges among different Staphylococcus strains suggesting that they could be included in cocktail formulations for therapeutic or bio-control purpose. Phage particle proteomes, consisting on average of ca 60-70 gene products, revealed, in addition to straight-forward structural proteins, also the presence of enzymes such DNA polymerase, helicases, recombinases, exonucleases, and RNA ligase polymer. They are likely to be injected into the bacteria along with the genomic DNA to take over the host metabolism as soon as possible after infection.

中文翻译：

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具有治疗和生物控制潜力的葡萄球菌噬菌体生物勘探。

抗生素耐药细菌的出现对公众健康构成严重威胁。金黄色葡萄球菌和其他葡萄球菌也是如此。葡萄球菌噬菌体 Stab20、Stab21、Stab22 和 Stab23 在阿尔巴尼亚分离出来。基于基因组和系统发育分析，它们被分类为Twortvirinae亚科的Kayvirus属。在这项工作中，我们描述了电子显微镜证实为肌病毒的噬菌体的深入表征。这些噬菌体能够耐受 5.4 至 9.4 的 pH 范围、25 µJ/cm2 的最大紫外线辐射能量、高达 45 °C 的温度和高达 25% 的乙醇浓度，并且对氯仿具有完全耐受性。噬菌体的吸附速率常数范围为1.0×10-9 mL/min至4.7×10-9 mL/min，突发大小为42至130个噬菌斑形成单位。噬菌体 Stab20、21、22 和 23 最初使用木糖葡萄球菌作为宿主分离，在不同葡萄球菌菌株中表现出不同的宿主范围，表明它们可以包含在用于治疗或生物防治目的的鸡尾酒制剂中。噬菌体颗粒蛋白质组平均由约 60-70 个基因产物组成，除了直接的结构蛋白外，还揭示了 DNA 聚合酶、解旋酶、重组酶、核酸外切酶和 RNA 连接酶聚合物等酶的存在。它们很可能与基因组 DNA 一起被注射到细菌中，以便在感染后尽快接管宿主的新陈代谢。